Premium
Physicochemical and Mineralogical Characterization of Soil–Saprolite Cores from a Field Research Site, Tennessee
Author(s) -
Moon JiWon,
Roh Yul,
Phelps Tommy J.,
Phillips Debra H.,
Watson David B.,
Kim YoungJin,
Brooks Scott C.
Publication year - 2006
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2005.0123
Subject(s) - saprolite , environmental chemistry , soil water , bioremediation , chemistry , illite , cation exchange capacity , environmental remediation , clay minerals , mineralogy , environmental science , geology , contamination , soil science , paleontology , ecology , biology , bacteria
ABSTRACT Site characterization is an essential initial step in determining the feasibility of remedial alternatives at hazardous waste sites. Physicochemical and mineralogical characterization of U‐contaminated soils in deeply weathered saprolite at Area 2 of the DOE Field Research Center (FRC) site, Oak Ridge, TN, was accomplished to examine the feasibility of bioremediation. Concentrations of U in soil–saprolite (up to 291 mg kg −1 in oxalate‐extractable U o ) were closely related to low pH (ca. 4–5), high effective cation exchange capacity without Ca (64.7–83.2 cmol c kg −1 ), amorphous Mn content (up to 9910 mg kg −1 ), and the decreased presence of relative clay mineral contents in the bulk samples (i.e., illite 2.5–12 wt. %, average 32 wt. %). The pH of the fill material ranged from 7.0 to 10.5, whereas the pH of the saprolite ranged from 4.5 to 8. Uranium concentration was highest (about 300 mg kg −1 ) at around 6 m below land surface near the saprolite–fill interface. The pH of ground water at Area 2 tended to be between 6 and 7 with U concentrations of about 0.9 to 1.7 mg L −1 These site specific characteristics of Area 2, which has lower U and nitrate contamination levels and more neutral ground water pH compared with FRC Areas 1 and 3 (ca. 5.5 and <4, respectively), indicate that with appropriate addition of electron donors and nutrients bioremediation of U by metal reducing microorganisms may be possible.